If you have been already familiar with filtration, prefiltration would not be new to you. For many filtration processes, a prefiltration is necessary. Have you ever thought about why we need prefiltration? And what is the effect of prefiltration? Especially in RO system, a prefiltration is important and essential.

Why need pre-filtration before high-pressure pump

In this article, we will talk about the relationship between prefiltration and high-pressure pumps in RO systems. And we will introduce connected knowledge about prefiltration. We believe you will know more about filtration and prefiltration after reading the blog.

What is the high-pressure pump?

Now, let’s move on to the RO system. It is known that the RO system needs pressure to accomplish the reverse process. And this kind of pressure comes from the high-pressure pump.

The working principle of RO is by using a high-pressure pump to increase pressure on the side of the high-concentrated solution and force the solution to pass through the semi-permeable RO membrane.

What is the high-pressure pump

To confront the natural characteristic of the solution, this external pressure is necessary and vital, which ensures the work of the RO system. The high-pressure pump can be regarded as the energy supplier and heart of the RO system.

Both the primary RO high-pressure pump and the secondary RO high-pressure pump adopt high-efficiency centrifugal water pumps. The full material of the pump body is generally stainless steel 304, the pump inlet is protected by low pressure, and the pump outlet is protected by high pressure.

ro plant

The high-pressure pump adopts frequency conversion control, which has the characteristics of strong power, stable transmission, and constant pressure water supply, which provides support for the stable water output of the subsequent RO system.

After realizing the importance of a high-pressure pump, it is crucial to keep the running the good condition of it. It spends a lot to do maintenance for high-pressure pumps, but we have to do it.

To reduce the frequency and cost of maintenance for the high-pressure pumps, many manufacturers require the end-users to do protection filtration which is prefiltration before high-pressure pumps. Most of them have also mentioned or suggested a specific micron rating.

Why need the prefiltration for the high-pressure pumps?

It is the most concerning problem on this topic. But we now already know the importance and necessity of high-pressure pumps. The contaminants and impurities in the water can cause damage to the high-pressure pump, which impacts the efficiency of the whole RO system.

The initial cost of a high-pressure pump is expensive, and the maintenance costs and downtime also increase the production cost. Purer water is needed for the high-pressure pump, to keep it always at the best operating condition.

Why need the prefiltration for high pressure pump

A security filter (also called a precision filter) is usually set before the high-pressure pump, and its filtration accuracy is 5μm.

After the pretreated water passes through the security filter, the impurities larger than 5 μm in the water are removed before entering the subsequent processing unit, providing stable and reliable water intake for the subsequent RO system, avoiding damage to the high-pressure pump and RO membrane or fouling, reducing the processing load for RO system.

Case study from Brother Filtration

Brother Filtration , as a filtration expert, has years of filtration experiences and offers various filtration solution for different industries and applications. We have one case in Vietnam, which is brackish water reverse osmosis(BWRO) for fish breeding.

The feed water is surface groundwater, the operating pressure before the high-pressure pump is 3-4 bar and after the high-pressure pump is 8-10 bar, the operating temperature is around 25-38℃.

Case study from Brother Filtration

Our clients had set up a prefiltration system before the high-pressure pump to do the protection.  Unfortunately, the inner core of the cartridge filter can not hold high pressure and be squashed inside the housing.

So the service life of the cartridge filters is quite short, and let they have enormous losses owing to the damage to the high-pressure pump. Because the particles bypassed from the cartridge filter went inside the pump and caused damage to the pump.

The solution from Brother Filtration

After we got the information from the client and received the picture of the product, we found out the problem. The plastic material which was supplied by the previous manufacturer would be easily damaged under normal operating pressure of 3~4 Bar, not to speak of the 8~10Bar.

The cartridge filter inside, especially the part of the inner core, can not withstand the operating condition due to its worse quality and unqualified material. Due to the outside-inside flow direction, the pressure was always concentrated in the inner core.


At this point, we suggested our client to adopt Brother Filtration Max-T high flow cartridge filter, which could resist high pressure during filtration process. The result is until now they are satisfied with our product and our service.

Also, the quality of our filter cartridges is approved by our client. By utilizing our products, our client successfully saves annual costs for more than 50,000 dollars per year.

fish breeding

This is what Brother Filtration is passionate about and what Brother Filtration insists to do. We have helped many clients to solve their filtration problems and offered them better solutions.


The high-pressure pump is the heart and important part of the RO system, and prefiltration can benefit not only the high-pressure pump but the whole RO system. It is necessary and vital to have a prefiltration device before a high-pressure pump.

In long term, it’s a cost-saving decision and able to help you reduce the total costs. But you should also notice that only a high-quality prefiltration filter could be applied, otherwise, the damage might be caused and brings more loss.

Brother Filtration has years of filtration experience and designs and manufactures all kinds of filter products, such as filter cartridges and filter housings.

We also provide better filtration solutions for our clients, we dedicate to solving all filtration problems. If you have any questions about prefiltration or filtration, please feel free to contact us.

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